Current strength, temperature, and bodyscape modulate cleaning services for giant manta rays

AbstractThe cleaner–client system among reef teleosts has received considerable attention in both wild and captive environments, but the spatially and taxonomically diverse associations between cleaner fish and elasmobranchs are less understood. Using remote video, we investigated interactions between giant manta rays (Mobula birostris) and cleaner wrasse at a seamount in the Philippines. Cleaning events occurred between 11:00 and 16:00 h on a seasonal basis and were constrained by current strengths and ambient water temperatures. The frequency with which giant manta rays interacted with cleaner fish varied on an individual basis. Blue streaked cleaner wrasse (Labroides dimidiatus) and moon wrasse (Thalassoma lunare) selectively foraged on manta rays’ gills and pelvis, with L. dimidiatus also demonstrating slight preferences for the pectoral fins. Cleaners’ foraging preferences may indicate ectoparasitic infections in specific areas of a manta ray’s body. The exclusivity with which giant manta rays visited a particular cleaning station on the seamount may be a response to the quality of services that cleaners provide there. Giant mantas’ fidelity to this site may also be attributed to localised concentrations of food that are available nearby. The seamount provides habitat that appears to be important to the life history strategies of the region’s giant manta rays.